1. Field of the Invention
This invention relates to novel synthesis of conjugated linoleic acid (CLA). In one aspect, this invention relates to novel synthesis of 9-cis, 11-trans octadecadienoic acid, also known as 9(Z),11(E)-octadecadienoic acid.
2. Background
Conjugated linoleic acid (CLA) is a general term used to name positional and geometric isomers of linoleic acid.
Linoleic acid is a straight chain carboxylic acid having double bonds between the ninth and tenth carbons and between the twelfth and thirteenth carbons. Linoleic acid is 9-cis, 12-cis octadecadienoic acid (9(Z),12(Z)-octadecadienoic acid). The numbers are counted from the carboxylic acid moiety. See Formula (1). ##STR1##
Conjugated linoleic acid (CLA) has two conjugated double bonds between the ninth and the twelfth carbons or between the tenth and thirteenth carbons, with possible cis and trans combinations. Conjugated double bonds means two or more double bonds which alternate in an unsaturated compound as in 1,3 butadiene. The hydrogen atoms are on the same side of the molecule in the case of cis. The hydrogen atoms are on the opposite side of the molecule in the case of trans. See Formula (2). ##STR2##
The free, naturally occurring conjugated linoleic acids (CLA) have been previously isolated from fried meats and described as anticarcinogens by Y. L Ha, N K. Grimm and M. W. Pariza, in Carcinogenesis, Vol. 8, No. 12, pp. 1881-1887 (1987). Since then, they have been found in some processed cheese products (Y. L. Ha, N. K. Grimm and M. W. Pariza, in J. Agric. Food Chem., Vol. 37, No. 1, pp. 75-81 (1987)).
Cook et al. U.S. Pat. No. 5,554,646 disclose animal feeds containing CLA, or its non-toxic derivatives, e.g., such as the sodium and potassium salts of CLA, as an additive in combination with conventional animal feeds or human foods. CLA makes for leaner animal mass.